P1108
NissanDual Alternator Battery Lamp Circuit Malfunction
Medium SeverityThe P1108 code indicates a fault in the warning light circuit for the secondary alternator, meaning the vehicle's electrical system may not be properly monitoring charging. This can lead to a dead battery or issues with electrical accessories if the charging system fails without warning.
⚠️ Before You Begin (Safety First)
Always disconnect the negative battery terminal before working on electrical components to prevent accidental shorts or injury. Ensure the vehicle is off and cooled down before inspecting engine components.
Common Symptoms
- Battery warning light on or flickering
- Intermittent or no charging
- Dim headlights or interior lights
- Vehicle failing to start due to a dead battery
- Electrical accessories malfunctioning
Common Causes
- Faulty wiring or connector in the battery lamp circuit
- Failed battery warning lamp or instrument cluster issue
- Malfunctioning secondary alternator
- Faulty voltage regulator (often integrated with the alternator)
- Blown fuse related to the charging system
Frequently reported on: Nissan Titan (2004-2015, V8 models), Nissan NV2500 (2012-2021), Nissan NV3500 (2012-2021), Nissan Titan XD (2016-2024, Diesel models)
Diagnostic Steps
- Inspect the battery terminals for corrosion and ensure they are clean and tight.
- Check all fuses related to the charging system and the instrument cluster for any blown fuses.
- Visually inspect the wiring harness connecting to the secondary alternator and the battery lamp for any signs of damage, fraying, or loose connections.
- With the engine off, use a multimeter to check the resistance and continuity of the battery lamp circuit wires as per the vehicle's service manual.
- If possible, test the secondary alternator's output and the voltage regulator's function using a multimeter or a specialized alternator tester.
👨🔧 When to Call a Professional
If the battery warning light is continuously on or flickering, or if you notice other electrical issues, consult a professional technician immediately as a charging system failure could leave you stranded.
Commonly Asked Questions
What does P1108 mean for my Nissan?
P1108 indicates a problem with the circuit for the battery warning light associated with your vehicle's secondary alternator. This means the system isn't properly monitoring or signaling the status of that charging component.
Is it safe to drive with a P1108 code?
Driving with a P1108 code is risky. While the primary alternator might still be working, a malfunction in the secondary alternator's warning light circuit means you might not get a warning before a full charging system failure, potentially leaving you stranded with a dead battery.
Can a P1108 code cause my battery to die?
Yes, indirectly. If the secondary alternator fails and the warning light circuit isn't working, you might not be alerted until your battery is significantly discharged or completely dead due to insufficient charging.
What's the first thing I should check if I get a P1108 code?
Start by checking your battery terminals for cleanliness and tightness, then inspect all fuses related to the charging system and the instrument cluster. Also, visually inspect the wiring around the secondary alternator for any obvious damage.
Do all Nissan vehicles have a dual alternator system?
No, dual alternator systems are typically found in Nissan vehicles that require higher electrical output, such as certain heavy-duty trucks (like the Titan) or commercial vans (like the NV series) that might have extensive aftermarket electrical accessories or specialized equipment.